The present invention relates to substrates having prolonged fragrance. More particularly, the present invention provides compositions and methods for reducing the loss of perfume during manufacture.
Fabric softener sheets typically include a substrate, a fabric conditioner base and a fragrance. The fabric conditioner base is used to impart a benefit to a fabric treated therewith. Such a benefit may include, for example, softness, reduced static of dried articles, easier ironing, etc. The fragrance is a used to impart a pleasant aroma to the dried fabric.
In use, these fabric softener sheets are typically placed in a conventional dryer together with fabric to be dried, e.g., wet laundry. During the drying process, fragrance and other benefits are transferred from the fabric softener sheet to the fabric being dried.
Conventionally, a fabric softener sheet is manufactured by coating a mixture of fabric conditioner base and fragrance onto a substrate. Typically, fabric softener bases are solid mixtures that must be melted prior to use. In practice, fabric conditioner bases are melted in a holding tank at about 70xc2x0 C. to 90xc2x0 C. then fragrance is added. Depending on the speed of coating, the conditioner base and fragrance may remain at these elevated temperatures for 4 to 8 hours. Fabric softener sheets are coated by continuously passing a substrate, e.g., a polyester sheet material, at high speed through a coating tank that is also held at 70xc2x0 C. to 90xc2x0 C. The coated sheet material is then passed through a series of cooled rollers and a cooling tower to reduce the sheet temperature to about 30xc2x0 C.
Fragrance losses occur at various points during the conventional fabric sheet manufacturing process; these losses in total may be up to 30 percent to 45 percent.
Encapsulates, such as cyclodextrin compositions as outlined in Bacon, et al., U.S. Pat. No. 5,348,667, have been used to reduce perfume loss during the manufacturing process. Such encapsulation technology, however, is expensive to make and use, and is therefore not cost effective in a large-scale commercial setting.
Absorbents have been used to carry lipophilic materials such as fragrance in the manufacture of certain products. For example, it is known that solids can adsorb oily materials, such as, perfume. Such adsorbent solids have been reportedly used as carpet cleaning powders (U.S. Pat. No. 5,783,543 and U.S. Pat. No. 5,286,400), in oil adsorbent products (U.S. Pat. No. 4,537,877 and U.S. Pat. No. 5,763,083), in detergent powders (U.S. Pat. No. 5,656,584), in detergent liquids (U.S. Pat. No. 4,983,422 and U.S. Pat. No. 4,209,417), in detergent bars (EP 816484), and in liquid softeners (U.S. Pat. No. 4,954,285).
Accordingly, one object of the present invention is to provide a process for producing a fabric softener sheet which process significantly reduces the loss of the perfume in the fragrance matrix during the manufacture of such a sheet compared to conventional processes.
Another object of the invention is to provide a substrate having prolonged fragrance compared to conventionally prepared substrates.
Another object of the invention is to provide an efficient, cost-effective method for reducing the loss of perfume during the manufacture of fabric softener sheets.
The present invention is directed to meeting these and other objects.
The present invention provides a process for reducing fragrance loss during the manufacturing of fragranced substrates. This process includes providing a protected fragrance matrix that contains a perfume, a solid absorbent and optionally a fixative. In this process, a fabric conditioner base is further provided. A substrate is then combined with the fragrance matrix and the fabric conditioner base. A substrate treated in this manner retains more of the fragrance compared to conventionally prepared substrates.
The present invention also provides a substrate impregnated with a fragrance matrix having prolonged organoleptic activity. This substrate is made by the process of forming a protected fragrance matrix that includes a perfume, an optional fixative and a solid absorbent. The fragrance matrix is then combined with a fabric conditioner base. The fragrance matrix and fabric conditioner base are then applied to the substrate either together as a mixture or sequentially. In this process, the fragrance matrix is combined with the fabric conditioner base immediately prior to application of the mixture to the substrate. Alternatively, the fragrance matrix is applied to the substrate immediately after the fabric conditioner base.
The present invention provides a low cost method of reducing the loss of perfume during the manufacture of, e.g., a fabric softener sheet. This process includes the addition of a protected, i.e., an enrobed perfume contained within a fragrance matrix to a fabric conditioner base prior to application of the fabric conditioner base onto or into a substrate or during one of the rolling stages of a conventional fabric softener sheet manufacturing process. By using the process of the present invention, it is easier to dose, i.e., apply the fragrance to the substrate during the manufacturing process when the perfume is in a solid carrier form.
Thus, the process of the present invention includes ( 1) preparing a fragrance matrix including an enrobed, i.e., a protected perfume, an optional fixative and a solid absorbent; and ( 2) combining the fragrance matrix with a fabric conditioner base and a substrate.
As used herein, the phrase, xe2x80x9cfabric softener sheetxe2x80x9d includes a substrate, a fabric softener base and a fragrance matrix. For purposes of the present invention, the term xe2x80x9csubstratexe2x80x9d is intended to mean any material that acts as a delivery vehicle for the fragrance matrix and fabric conditioner base. Thus, in the present invention, the substrate must be able to retain in its interior or on its surface a sufficient quantity of the fabric conditioner base and fragrance matrix required to deliver the desired performance (prolonged fragrance) to the fabric, e.g., a fabric softener sheet. Typically, the substrate is in the form of a sheet, although other forms may be used. The substrate may be a synthetic or natural fiber that is woven, knitted or extruded. Non-limiting examples of materials that may be used as a substrate in the present invention include cotton, Rayon, polyester, regenerated cellulose, and the like.
As used herein, the phrases xe2x80x9cfragrance matrixxe2x80x9d or xe2x80x9cprotected fragrance matrixxe2x80x9d mean that at least the most volatile parts of a perfume are protected or enrobed by a solid absorbent and optionally a fixative to reduce the amount of loss of fragrance during the manufacturing process of a substrate through evaporation of the perfume volatiles.
In the present invention, the protected fragrance matrix is said to xe2x80x9cenrobexe2x80x9d the perfume. Thus, as used herein, the terms xe2x80x9cenrobe,xe2x80x9d xe2x80x9cenrobedxe2x80x9d or xe2x80x9cenrobementxe2x80x9d refer to the sequestration of the perfume in the protected fragrance matrix to reduce the loss of fragrance during the manufacture of fragranced substrates, e.g., fabric softener sheets, and to prolong the effect of a fragrance on substrates coated with such an enrobed perfume.
The protected fragrance matrix is preferably in the form of a flowable powder. Thus, the ratio of perfume, solid absorbents and fixative are carefully controlled to maintain the consistency of a flowable powder. In this embodiment, the perfume-to-solid absorbent ratio is between about 1:20 to about 2:5, preferably about 1:5. The level of perfume, however, will depend upon the final composition of the substrate. The fragrance, in turn, may be present in the protected fragrance matrix in an amount of from about 10% to about 50% (wt/wt), preferably, in an amount of from or between about 20% to about 40% (wt/wt). On the substrate, the fragrance level will be about 1% to about 6% (wt/wt).
The flowable powder may be dosed into, for example, a molten fabric conditioner base such as a softener or an antistatic system. Preferably, the powder is mixed into the fabric conditioner base immediately prior to application of the mixture to the substrate. Alternatively, the powder is applied to a substrate previously coated with the fabric conditioner base at a subsequent processing step, such as at one of the rolling stations during the manufacture of a fabric softener sheet.
As used herein, the term xe2x80x9cimmediatelyxe2x80x9d is intended to mean that the fragrance matrix is added to the fabric conditioner base just prior to application to the substrate. Typically, the fragrance matrix is added 1-20 minutes prior to application to the substrate, preferably 2-10 minutes prior to application to the substrate; most preferably the fragrance matrix is dosed at the rolling stage directly onto the substrate coated with the fabric conditioner base.
In the present invention, the protected fragrance matrix may contain all or part of the perfume. If part of the perfume is protected, i.e., enrobed, then it is usual to select the most volatile components to be enrobed.
For example, in the present invention, the protected fragrance matrix is formed into a powder by mixing the perfume with an absorbent solid and an optional fixative. Absorbent solids that may be used in accordance with the present invention include, for example, clays, silicas, Celites, Zeolites, metal salts, including for example phosphates, cellulose, such as methyl cellulose, starches, carbonates, such as sodium bicarbonate, borates, such as sodium borate, sulfates, such as sodium sulfate, water-soluble polymers, Borax and mixtures thereof.
For purposes of the present invention, the term xe2x80x9cperfumexe2x80x9d is intended to mean a mixture of a single or complex mixture of aromatic chemicals which have been formulated to give an aesthetically pleasing smell to a substrate, such as for example, a fabric softener sheet. As used herein, xe2x80x9caroma chemicalsxe2x80x9d are intended to mean chemicals that have an odor. There are many chemical classes which fall within the meaning of the phrase xe2x80x9caroma chemicalsxe2x80x9d as used herein, including for example, hydrocarbons, alcohols, aldehydes, ketones, lactones, esters. These chemical classes are described in S. Arctander Perfume Flavors and Chemicals, Vols. 1 and 2, Arctander, N.J. USA which also is hereby incorporated-by-reference.
The perfume may also contain small amounts of other additives, such as solvents, preservatives, antioxidants, UV screening agents and the like. The fragrance matrix may also include organoleptic components, such as for example, other well-known fragrance ingredients.
Preferably, a fixative is incorporated into the fragrance matrix of the present invention. The fixative preferably is a high molecular weight, low melting solid composition that may be mixed into a powder. Examples of suitable fixatives for use in the present invention include polyethylene glycol, Glycerox, mineral oil and mixtures thereof. In accordance with the present invention, the molecular weight of the fixative may vary between about 400 to 20,000 daltons, preferably between about 2,000 to 10,000 daltons. Other fixatives having a similar viscosity and melting point to polyethylene glycol are also contemplated by the present invention. The level of fixative useful in accordance with the present invention is between about 1% and about 40% (wt).
The solids and the liquids set forth above are combined by, for example mixing in a suitable mixer until the blend is flowable so that it is easy to apply (i.e., dose) to a substrate.
The present invention also includes a fabric conditioner base. For purposes of the present invention, the fabric conditioner base includes a mixture of ingredients that impart a desired property to the fabric, such as for example, softness, no static cling, reduced creasing, easier ironing, and the like. These properties are achieved using, for example, cationic, zwitterionic, and non-ionic softeners, soaps and quaternary compounds, as well as other fatty materials alone or in combination. Other examples of suitable fabric softener bases may be found in U.S. Pat. No. 3,686,025, which is hereby incorporated by reference as if recited in full herein.
Other optional components may also be added to the fabric conditioner base to further impart various desired characteristics to the substrate, so long as these ingredients do not significantly interfere with the reduction of fragrance loss during manufacturing of substrates. Such optional components include, for example, antistatic agent(s), anti dye-transfer agent(s), soil release agent(s), and the like.
In the process according to the present invention, the substrate may be coated at several carefully timed points and according to a specific sequence of events to achieve the desired fragrance effect. For example, in one embodiment, the substrate may be coated by combining the fragrance matrix with the fabric conditioner base to form a mixture immediately prior to applying the mixture to the substrate. Alternatively, the substrate is coated by applying the fabric conditioner base thereto to form a substrate-fabric conditioner base composition. Thereafter, the fragrance matrix is applied to the coated substrate.
For purposes of the present invention, the fragrance matrix and/or fabric conditioner base is applied to the substrate using any conventional technique suited for the particular application, such as, for example, spraying, coating, dipping and the like. Using these and other techniques, the fragrance matrix and fabric conditioner base are applied to the substrate as a coating. Alternatively, the fragrance matrix and fabric conditioner are impregnated throughout the substrate, i.e., are dispersed within the interstitial matrix of the substrate as well as its surface.
Preferably, the fabric conditioner base and fragrance matrix are dispersed throughout the substrate to a uniform thickness of about 0.1 to about 2 mm to evenly distribute the fragrance throughout the entire substrate.
Another embodiment of the present invention is a substrate impregnated with a fragrance matrix having prolonged organoleptic activity. This substrate is made by the process which includes (a) forming a protected fragrance matrix as set forth previously with a perfume, a fixative and a solid absorbent; and (b) mixing the fragrance matrix with the fabric conditioner base immediately prior to applying the mixture to the substrate or applying the fragrance matrix to the substrate immediately after the fabric conditioner base is applied to the substrate.
Thus, in one embodiment, a mixture of the fragrance matrix and fabric conditioner base is applied to the substrate. In this embodiment, the fragrance matrix is added to the fabric conditioner immediately prior to application of the mixture to the substrate. Alternatively, the fabric conditioner base and fragrance matrix are applied to the substrate sequentially. In this embodiment, the fabric conditioner is applied to the substrate first, immediately followed by the fragrance matrix.
The fixative according to this embodiment is selected from high molecular weight, low melting point compositions such as for example, polyethylene glycol, Glycerox, mineral oil and mixtures thereof.